250 植物研究雑誌 第 91 巻 第 4 号 2016 年 8 月

J. Jpn. Bot. 91: 250–253 (2016)

Kenji Suetsugu: A New Color Variant of the Mycoheterotrophic Orchid septentrionalis from Hiroshima Prefecture, Japan

Department of Biology, Graduate School of Science, Kobe University, 1-1, Rokkodai, Nada-ku, Kobe, 657-8501 JAPAN E-mail: [email protected]

Summary: It is well documented that some color. Cyrtosia septentrionalis with yellow fruits mycoheterotrophic have distinct color are called “Kimino-Tsuchiakebi” in Japanese variations. Here, I describe a new form of (Satomi 1982). However, the mutant was Cyrtosia septentrionalis from Hatsukaichi City, published without its scientific name and the Hiroshima Prefecture, western Japan. Ecological type specimen (Satomi 1982). significance of this yellow form of Cyrtosia septentrionalis is also discussed. Taxonomic treatment Cyrtosia Blume () is a small Cyrtosia septentrionalis (Rchb. f.) Garay genus of orchids comprising approximately 10 f. flava Suetsugu, f. nov. [Fig. 1] species distributed throughout the temperate The newly discovered specimens differ from and tropical regions of , Japan, Taiwan, Cyrtosia septentrionalis f. septentrionalis only in Thailand, and Indonesia (Averyanov 2011). This the yellow coloration of their flowers and fruits. group of fully mycoheterotrophic plants belongs Type: JAPAN. Honshu: Hiroshima Pref., to the subfamily and is closely Hatsukaichi City, Yoshiwa. 7 November 2015, related to the genus Galeola Lour. (Cameron Shunichi Wakasaki s.n. (OSA_C794–holotype). 2009). Although Cyrtosia and Galeola are Japanese name: Ki-mi-no-tsuchi-akebi very similar in appearance in sharing yellow (Satomi 1982). or reddish brown tinged flowers, tuberous 和名：キミノツチアケビ（里見 1982）． rhizomes, and persistent floral bracts and scales Note: The distribution of Cyrtosia at their nodes (Yumkham et al. 2013), they can septentrionalis f. flava discovered in the present easily be distinguished (Yumkham et al. 2013) study is restricted to a broad-leaved deciduous according to the morphology of their stems forest dominated by Quercus acutissima Carruth, (erect vs. erect or scrambling vines), sepal-petal Q. crispula Blume, Fagus japonica Maxim., orientation (not fully open, sepals and petals and Carpinus tschonoskii Maxim. that is located connivent vs. fully open), fruits (fleshy berry, near Yoshiwa, suburb of Hatsukaichi City in indehiscence vs. dry capsule, dehiscent), and Hiroshima Prefecture, Japan. The type locality is seeds (narrow or no wing vs. prominent broad the mixed population of Cyrtosia septentrionalis wing). f. septentrionalis and C. septentrionalis f. flava, It is well documented that certain groups of harboring ca. 10 flowering individuals of each mycoheterotrophic plants have distinct color form. The greatest distance between individual variations (e.g., Fukunaga et al. 2008, Suetsugu C. septentrionalis f. flava plants appears to be 2012a, b, Tsukaya and Okada 2012, Suetsugu further than 3 km, while the nearest distance and Yagame 2014, Suetsugu 2016). Here, I between C. septentrionalis f. septentrionalis and describe a new form of Cyrtosia septentrionalis C. septentrionalis f. flava is ca. 300 m. whose flowers and fruits are bright yellow in Similar color variants have also been August 2016 The Journal of Japanese Botany Vol. 91 No. 4 251

Fig. 1. Cyrtosia septentrionalis (Rchb. f.) Garay f. flava Suetsugu, from the type locality (a–­b). C. septentrionalis f. septentrionalis from Higashinomi City, Shiga Pref., Japan (c–d). a, c. Flowering individual. b, d. Fruiting individual. Bar = 5 cm. 252 植物研究雑誌 第 91 巻 第 4 号 2016 年 8 月 discovered and are called “Kimino-Tsuchiakebi” Cyrtosia septentrionalis f. flava could in fact be in Japanese (Satomi 1982), though the mutant disadvantageous to seed dispersal. However, has not been formally described with the type it is also possible that the species assemblage specimen. For example, Cyrtosia septentrionalis of seed dispersal agents in the habitats of C. with yellow fruits were discovered in Morioka septentrionalis f. flava and f. septentrionalis City, Iwate Prefecture, which is over 1000 differ, and it would therefore be interesting to kilometers away from the type locality of investigate whether the new form f. flava also Cyrtosia septentrionalis f. flava (Mahoro Suzuki utilizes ornithochory, and which species are the pers. comm.). Taken together, these observations predominant dispersal agents. indicate that the evolution of this color variant has probably occurred at multiple locations. I thank Shunichi Wakasaki and Chisato Ohe Flowering in the new form Cyrtosia for their discovery and assistance in the field septentrionalis f. flava occurred from early to late study. I also thank Dr. Takahiro Yagame for July with fruiting from early to late November providing the picture of a flowering Cyrtosia in the type locality. Although there were no septentrionalis f. flava individual. I also thank differences in morphology, C. septentrionalis Dr. Mahoro Suzuki for the useful discussion. f. flava could easily be distinguished from f. This work was supported by a Grant-in-Aid septentrionalis by the coloration of its petals and from the Japan Society for the Promotion of sepals (bright yellow vs. pinkish white to whitish Science (15K18470 to K.S.). orange) and fruit (bright yellow vs. bright red). Although the selective pressure for References photosynthetic pigments is relaxed in Averyanov L. V. 2011. The orchids of Vietnam. Illustrated mycoheterotrophic plants, pigmentation is still a survey. Part 3. Subfamily Epidendroideae (primitive vital component in biological interactions such tribes–Neottieae, , Gastrodieae, Nervilieae). as pollination or seed dispersal. However, since Turczaninowia 14(2): 15–100. Cameron K. M. 2009. On the value of nuclear and C. septentrionalis utilizes autonomous self- mitochondrial gene sequences for reconstructing pollination as dominant strategy to ensure fruit the phylogeny of vanilloid orchids (Vanilloideae, set (Suetsugu 2013), it seems to be less likely Orchidaceae). Ann. Bot. 104: 377–385. that any color changes in this species would be Eriksson O. and Kainulainen K. 2011. The evolutionary ecology of dust seeds. Perspectives in Ecology, a response to pollinator preference. Despite this, Evolution and Systematics 13: 73–87. it is possible that the color change could provide Fukunaga H., Sawa S. and Sawa Y. 2008. A new form of some selective pressure since recent observation Lecanorchis kiusiana. Orchid Rev. 116: 106–108. suggests that in contrast to most orchids, which Gautier-Hion A., Duplantier J. M., Quris R., Feer F., disperse their tiny dust-like seeds by wind Sourd C., Decoux J. P., Dubost G., Emmons L., Erard C., Hecketsweiler P., Moungazi A., Roussilhon C., (Eriksson and Kainulainen 2011), Cyrtosia Thiollay J. M. and Thiollay J. M. 1985. Fruit characters septentrionalis utilizes birds as dispersal agents as a basis of fruit choice and seed dispersal in a tropical (Suetsugu et al. 2015). Compared to other forest vertebrate community. Oecologia 65: 324–337. orchids, C. septentrionalis has several unusual Satomi S. 1982. Orchidaceae. In: Satake Y., Ohwi J., Kitamura S., Watami S. and Tominari T. (eds.), Wild morphological characteristics including fleshy, Flowers of Japan, Herbaceous Plants including Dwarf red, indehiscent fruits and seeds with a lignified Subshrubs. pp. 187–235. Heibonsha, Tokyo (in testa that could be considered adaptations Japanese). to ornithochory (Suetsugu et al. 2015). In Suetsugu K. 2012a. A new form of Gastrodia confusa general, ornithochory is associated with red (Orchidaceae). J. Phytogeogr. Taxon. 59: 125–126. Suetsugu K. 2012b. New record of the mycoheterotrophic fruits that attract frugivorous birds (Gautier- orchid Lecanorchis kiusiana forma lutea outside the Hion et al. 1985), so the yellow coloration of type locality. J. Phytogeogr. Taxon. 60: 35–37. August 2016 The Journal of Japanese Botany Vol. 91 No. 4 253

Suetsugu K. 2013. Autogamous fruit set in a Suetsugu K. and Yagame T. 2014. Color variation of the mycoheterotrophic orchid Cyrtosia septentrionalis. mycoheterotrophic Yoania japonica (Orchidaceae). Plant Syst. Evol. 299: 481–486. Acta Phytotax. Geobot. 65: 49–51. Suetsugu K. 2016. A new color variant of the myco- Tsukaya H. and Okada H. 2012. A color variation of heterotrophic orchid Gastrodia fontinalis from Epirixanthes species (Polygalaceae) found in West Takeshima Island, Japan. Acta Phytotax. Geobot. 67: Kalimantan, Borneo, Indonesia. Acta Phytotax. Geobot. 55–59. 62: 95–97. Suetsugu K., Kawakita A. and Kato M. 2015. Avian seed Yumkham S. D., Chakpram L., Benniamin A. and Singh P. dispersal in a mycoheterotrophic orchid Cyrtosia K. 2013. Discovery of Cyrtosia nana (Orchidaceae) in septentrionalis. Nat. Plants 1: 15052. India. Taiwania 58: 229–232.

末次健司：菌寄生性ラン科植物ツチアケビの色彩変異 通常，果実が赤色を呈するツチアケビでは，稀に黄色 黄色であることから，開花期においても，母種と区別で の果実をつける個体が見られることがある．黄色の果 きる．和名は里見に従いキミノツチアケビとする．ツチ 実をつけるツチアケビには，里見 (1982) によりキミノ アケビは，鳥による被食動物散布を採用していることが ツチアケビとの和名が付けられたが，正式には記載さ 報告されており，赤色の果実は鳥散布への適応であると れていない．そこで広島県廿日市で採取された個体を， 考えられている．よって，今後，黄色の果実をつけるキ 新 品 種 Cyrtosia septentrionalis (Rchb. f.) Garay f. flava ミノツチアケビの種子散布効率や種子散布者相の調査 Suetsugu として記載した．また母種の花被片が白味を が望まれる． 帯びた橙色であるのに対し，本品種の花被片は鮮やかな （神戸大学大学院理学研究科）